Open Positions

We are currently looking for Masters and Ph.D. students and postdoctoral researchers interested in quantum optics and quantum information processing to join Sharif Quantum Center!

Publications

E. E. Moghaddam, H. Beyranvand and J. A. Salehi, "Resource Allocation in Space Division Multiplexed Elastic Optical Networks Secured with Quantum Key Distribution," in IEEE Journal on Selected Areas in Communications, doi: 10.1109/JSAC.2021.3064641.

Research Topics

1. Quantum Communications:

   Communication systems deal with the transmission of information from one or more sources to one or multiple destinations. As we are approaching the era of quantum information, proportionate communication systems should be developed. Quantum communications is an area of research that utilizes principles of quantum mechanics such as entanglement, superposition, time-evolution, and measurement to offer efficient solutions for communication systems. These quantum solutions enhance classical communication systems' security and performance and make quantum information transfer possible. The most important aspects of quantum communication research are:
   • Enhancing classical communication systems:
     Classical communications rely on the optimal detection for signal transmission through a physical medium such as fiber for optical and air or vacuum for wireless communication systems. Conventionally, these channels are modeled using classical or semi-classical physics. However, a more accurate model for many communication channels is attained by quantum mechanical descriptions. Therefore the transmitted and received signals are quantum states and can no longer be described as simple stochastic processes. In 1976, Helstrom developed the fundamental concepts of quantum communications for classical information transfer in terms of quantum detection theory. Since that time, this field became an active area of research.
   
   
   • Ultimate secure communications:
     Traditionally, secure communications such as public-key cryptography were based on computationally hard mathematical problems. With the development of quantum computers in future years, the classical schemes for secure communication will be broken. The fundamental aspects of quantum mechanics not only break the classical secure methods but also provide their own alternative. Based on the seminal work of Charles Bennett and Gilles Brassard in 1984, Quantum Key Distribution (QKD) enables the communication parties to share secure keys based on quantum mechanics concepts.
   
   
   • Transferring quantum information:
     Classical distributed systems and distributed computing are an essential part of current information processing networks. The rise of quantum computing and quantum information processing necessitates the transmission of quantum information inside the future distributed quantum networks enabling distributed quantum information processing. Hence, a quantum communication system should be able to transmit a quantum state carrying quantum information from a source to a destination. Advanced techniques such as quantum teleportation, quantum coding, and entanglement purification are the enablers of future distributed quantum networks.



2. Quantum Computations:

   Quantum computation is an area of scientific research that uses quantum mechanics features such as superposition and entanglement to perform and develop computations. The origins of quantum computations go back 1980s. However, a theoretical algorithm for an ideal quantum computer was first proposed in 1994. Since then, much attention has been paid to the quantum computations field, its applications, and the construction of quantum computers.
   Instead of classical computations bits (0 or 1), the basis of quantum computations is quantum bits or qubits that encode information in 1 or 0 quantum states or a superposition of 1 and 0 states. The qubits in quantum computations could be made of electrons, photons, atoms, and molecules. This superposition of states allows quantum computers to manipulate many combinations of states at the same time. Moreover, quantum computers are high-speed and efficient in the processes such as simulations of molecules, sorting, and optimizing. However, there are some significant challenges to constructing quantum computers. One of the greatest challenges is maintaining the superposition of quantum states from environmental effects or quantum decoherence. Therefore, quantum computers require error correction.
   
   The quantum computations models are classified based on the basic elements in which the computation is decomposed. Accordingly, the main models of quantum computations are:
   • One-way quantum computations
   • Adiabatic quantum computations and quantum annealing
   • Quantum gate array
   • Topological quantum computations
   Today, quantum computations can be used in a variety of fields. Some of the potential applications of quantum computations are:
   • Quantum supremacy
   • Computational biology
   • Search problems
   • Artificial intelligence
   • Simulation of quantum systems
   • Quantum annealing and adiabatic optimization
   • Machine learning
   It is believed that quantum computations could change our world and pave the way to developing various technologies and creating new technologies.




3. Quantum Information:

   In 1867 James Clerk Maxwell proposed his thought experiment, Maxwell’s demon in which it seems a demon with some information about a system can decrease the total entropy of a system without implementing any work, hence violating the second law of thermodynamics. Then, in 1961 Landauer proposed his principle, which states that information erasure is accompanied by heat dissipation, clarifying Maxwell’s demon paradox. In 1948 Claude Shannon discovered how to quantify Information. Since then, these two revolutionary phenomena have linked the information to the core of the physical processes. Information is carried with some physical or chemical signals that enfold meaning. Unfolding the meaning requires information processing. In the quantum domain, the information is carried with quantum states, and interestingly it is not independent of its physical support. Nowadays quantum information theory is the mathematical backbone of the quantum world and helps us to understand the nature of the quantum world. Also, as quantum mechanics introduce us to some exclusive features such as entanglement and correlated states, quantum information brings us unimaginable new applications and abilities. However, technologies of quantum information are not spread as their classical equivalent, yet.
   The branches of theoretical researches in quantum information contain:
   • Exploring the limits of quantum devices and investigating the performances of a variety of quantum systems such as atoms and superconducting qubits and understanding the advantages of each.
   
   
   • Studying and developing different areas in quantum communication and computation such as nanoscale magnetic sensing and long-distance quantum key distribution.
   • Understanding the role of dissipation in how it limits coherence in quantum systems, also considering it for cooling systems and error correction in quantum computation.
   • Furthermore, deriving and developing thermodynamics from quantum mechanics using quantum information theory is almost as old as quantum mechanics. These are very active research areas in recent years and caught the attention of many quantum information researchers.




4. Quantum Biology

   Quantum Biology is a growing field of scientific research that focuses on the roles of the principles of quantum mechanics such as superposition, tunneling, and entanglement in the biology world. The origins of quantum biology trace back to Erwin Schrödinger’s lecture series in Dublin Institute for Advanced Studies, published in 1944 as a book named ”What is Life.” In this book, he asked an important question: How the rules of physics and chemistry can describe biological phenomena?. In the past two decades, many researchers have tried to show quantum mechanics may assist or enhance a biological function. Today, the effect of quantum mechanics on some biological processes has been demonstrated. The most important of these are:
   • Quantum coherent energy transport in photosynthesis:
     The experimental observations show that some photosynthetic systems use coherent dynamics to transfer the energy of sunlight from the light-harvesting antenna to the reaction centers with near 100% efficiency. Understanding quantum coherent energy transport in photosynthesis can greatly help manufacture high-efficiency energy conversion technologies.
   
   
   • Magnetoreception in birds:
     It has been proposed that some species of birds migrate using the Earth's magnetic field based on a quantum approach named radical-pair mechanism. This mechanism is verifiable by creating spin-correlated states, singlet and triplet states, via photochemical reactions in the bird's eyes. The experimental observations confirmed that the radical pair of some chemical compounds were affected by the Earth magnetic field. Although there are open questions in this mechanism, it seems that an accurate understanding of the magnetoreception process in birds can help essential technologies such as sensitive magnetic sensors in orientation tools and medical diagnostic devices.
   • Quantum tunneling in biological systems:
     As we know, quantum tunneling is an essential feature of the quantum world. The experimental observations show that long-range electron tunneling through protein in biological redox reactions plays a vital role in photosynthesis and respiration processes. Moreover, the role of Hydrogen tunneling has been demonstrated in a wide range of biological reactions. For instance, proton tunneling between tautomeric forms of nucleic acids causes the point mutations in genetic.
   • Quantum effects in biological ion channels:
     The precise mechanism of selectivity in ion channels is still an open problem in biology for more than half a century. Recently, it has been suggested that quantum interference that occurs between similar ions passing through a neural ion channel can be a solution to explain the mechanism of selectivity in ion channels.